It attaches to the audio jack of most popular iOS and Android devices.
At the bottom of the Ascend D2 is a Dolby Digital Plus speaker with the standard audio jack rested next to it.
ENGADGET: Hands-on with the Huawei Ascend D2 (update: now with video)
The BlackShark plugs directly into any device with a 3.5mm audio jack, offering compatibility with nearly every audio device on the market today.
ENGADGET: Razer unveils its own BlackShark, black and green version ships next month for $120
The device has a unique audio amplifier that powers the 3.5mm audio jack and speaker to provide improved sound for music, video and even gaming.
ENGADGET: AT&T prices Lumia 920 and 8GB HTC 8X at $100, Lumia 820 at $50, Nokias due on Friday
Similar products typically spin on the audio jack, causing misreads of the credit card and requiring the user to awkwardly hold the product in place while swiping.
For anyone who has used one of these types of devices, the two standout features mentioned above should be the audio jack, and the addition of Bluetooth.
Another player in this space is Square, which offers a tiny card reader that attaches to the audio jack on an Android, iPhone, iPad or iPod Touch and reads a card.
FORBES: Shoot the Credit Card with a Mobile Phone to Accept Payment
It attaches to a smartphone or tablet via its audio jack, features a mini-headphone jack for monitoring, and offers a low-profile solution for capturing better sounding audio from a smartphone or tablet.
While the ever improving processing power and always-on broadband connectivity of the smartphone are the core assets, it has been interesting to see such widespread capabilities as the camera, GPS, and even audio jack used as hooks for new FinTech solutions.
FORBES: Why The Financial Technology Revolution Is Only Just Getting Started
The Windows Phone 8X by HTC featuring Beats Audio also offers a unique audio amplifier powering the 3.5mm audio jack and the speaker, boosting the audio signal for even better sound no matter if you're listening to music, playing a game or watching a video.
ENGADGET: Windows Phone 8X by HTC: 4.3-inch 720p display, LTE, dual-core S4, available this November
The Ghost Bee also comes with a base station that connects to the headphones via micro-USB and hooks up to any home stereo's 3.5mm audio-in jack.
Naturally, this is where you can jack up the audio resolution, too.
ENGADGET: Zoom Q2HD Handy Video Recorder lets you stream and record on the move, we go hands-on
It's being aimed at iPod owners but will work with any audio source with a compatible headphone jack--including PCs or laptops.
Audio can be monitored through the headphone jack and levels can be displayed on the LCD with peaking.
ENGADGET: Nikon unveils lightweight, full-frame D600 DSLR -- hands-on and low-light samples (video)
You can counteract that mic placement by adding your own audio capture device thanks to the standard microphone input jack that joins HDMI and USB connectors on the left side.
ENGADGET: Canon EOS M review: was Canon's first mirrorless ILC worth the four-year wait?
Furthermore, the device can sometimes be a nuisance depending on the placement of a guitar's input jack, not to mention dealing will two audio cords for headphones and a music source.
ENGADGET: Vox jams guitar amps into Audio-Technica headphones, dubs them Amphones (ears-on)
You may also play music from any audio device through the universal 3.5mm aux line-in jack.
ENGADGET: iHome intros iDM5 Executive workstation for tablets / smartphones, priced at $130
The IS9181 also includes an auxiliary audio cable to play files from MP3 or CD players or any other device with a 3.5mm headset jack.
ENGADGET: VTech plunges into home audio market with IS9181 WiFi radio
The Android 4.1 device's ports include Micro HDMI, TOSLink Optical audio, Ethernet, micro AB USB (for service and support only, Google says), and banana jack speaker outputs.
Somehow, though, MSI squeezed in an Ethernet jack and full-sized HDMI socket, along with two USB 3.0 connections, an audio port and a memory card reader, tucked around back.
ENGADGET: MSI Slidebook S20 review: MSI's flagship Windows 8 Ultrabook has a flawed design
应用推荐